Tuff Torq K46 Tranny

tucoMarch 2, 2008

I've been reading many of the posts on this site and there is varied opinion on the Tuff Torq K46 Tranny. Is it recommended that the fluid be changed every 100 hours or so and if "yes" how does one go about doing this. Also, what is better, conventional oil or synthetic?

I average about 50 hours/year - mainly just grass cutting, yard maintainance (dethatching, aerating, cart pulling, etc...) throughout the year and leaf clean-up in the fall. After reading a bunch of these posts I'm wondering if I should have bought an Army surplus tank or the like.

First off, the K46 is designed as a non serviceable transmission. Some people have reported good results from changing their oil, while others may have created more problems than they cured. I personally would not change the oil as a regular maintenance item, but I would think a 200 to 250 hour interval would be appropriate if you do, 4 to 5 years in your case. That said, I would not hesitate to change the oil, if and when, my transmission began to show symtoms, loss of speed, lack of torque, etc. and then adjust my oil change interval based on that. Be sure to keep things very clean if you do change the oil. I would use synthetic if I was going to change it.

You wouldn't change it as a 'regular maintenance' item . . . . unless the transmission begins to show signs that it's worn out (probably from pumping the same old contaminated oil around for 3 or 4 years) at which point you would change it? - Fix the gate latch after the horse is already out of the barn?

My Dad used to maintain cars like that . . . . and trade them in every 3 or 4 years

I think you guys are a little off base. As sadixon49 correctly pointed out, the transmission in question is not meant to be serviced on a regular basis. The sympton of the oil degrading is exactly how he describes. It's NOT the pump that goes bad because of the oil, the oil itself degrades. The oil in the transmission, for the most part, performs a totally different function than the oil in a car (it does provide lubrication, but the majority of its' fuction is the working media for a CLOSED hydraulic system). AND since the transmission is sealed, get's no blow by from the combustion cylinders, it stays clean. As the other posters pointed out, keep the fins clean, the oil cool and it will last for a VERY long time. Talk about easy targets.

True, no combustion blowby to contaminate the oil, but there is an atmospheric vent to prevent pressure from developing in the airspace above the oil. The vent is provided with a filter plug in some cases (or just a dust excluder cap in others) to keep out solid particles and dust. It does not, however, prevent water vapor (humidity) from being drawn in through the vent when the HST cools after a use cycle. This small amount of water (and other gaseous components in air) will slowly degrade the oil over time. It is true that the oil will last for a long time before it begins to break down and become ineffective (the oil loses its anti-foam properties and will no longer support hydraulic or hydrostatic functions when it retains air bubbles or "foams".) The sad part of the big picture is that the OEMs would rather sell the consumer a new tractor (or transmission) than to make it simple to change the HST oil.

All the points made are valid... but there is one point - which is key, and hasn't been mentioned yet. By the way, this point is not some theory - it's something I got straight from a TuffTorq engineer, while talking on the phone with him.....

As the hydraulic pump and motor inside the tranny are worked, friction causes the oil to heat up.... as the oil heats up, it starts to break down, eventually to a point where it burns as it attempts to cool the heated friction surfaces of the pump and motor. Once it burns it creates carbon particles, and it's the carbon particles that begin to affect the very highly mirror-like polished surfaces of the pump and motor. Once these surfaces are scored with the carbon particles, the pump and motor efficiency drops off.

This is why you want to keep the oil cool by keeping the fins and fan on the outside clean. But, at the same time, if you work your tranny hard - causing it to really heat up often, and for long periods of time, you want to swap out the oil to flush out the carbon particles.

The K46 tranny "is" designed to be serviced, but the "options" selected by OEMs such as JD are what causes grief for folks like us. The options for JDs K46 deleted the drain plug and expansion reservoir. Don't blame the tranny. Blame the "options" decisions made by JD.

But at the same time, keep in mind that a K46 driven tractor is meant to be low-cost, and short life. By deleting these options, JD can make the machine cheaper than what it otherwise would be. And because it's not a Garden Tractor, it's not meant to last 25 years.

However, changing out the fluid in a K46 is not impossible - it's just more hassle than what it would be if there was a drain plug.

I work my L120 very very very hard. I changed the oil at about 220 hours, and it was noticeably dark-amber, as opposed to new-oil light-amber color. A definite sign of breakdown. However, if all you do is mow grass, I would not bother to change the oil until maybe 300 to 400 hours

I agree completely. The question becomes, would you attempt changing the oil on a periodic schedule, or wait until symptons appear? Alternatively, if you wait for symptoms, have you caused irreversible mechanical damage? I think that is the answer the OP was seeking.

mownie, that's truue about changing the HST oil, and when's the last time you saw a drain plug on the bottom of an automatic transmission pan on a truck or a car. It's crazy, having to slowly back off the pan screws and brace yourself for the inevitable wave of transmission fluid that always spills out all over the place.

As wally2q pointed out (and I had not considered), there is a lot of heat generated when working a hydrostat. True enough, the "localized, point of pressure" may produce extreme heat and cause some carbon (and other by-products) to precipitate out of the oil. I guess all this plus the water vapor factor conspire to degrade the oil and not just a single factor.
lkbum, I think we should all pick some kind of HST oil change cycle that pre-empts total failure of the oil (or the HST assy) on our individual machines. I think a good average cycle would be every 200 hours (or 4 years based on 50 hrs per year). Considering the inherent difficulty of performing this task, I couldn't recommend everybody change the oil every season (though it would not cause harm so long as rigid cleanliness is practiced.
larso 1, right you are about the tranny drain plugs. A factory rep for Borg-Warner (who made the auto transmissions used in IH light duty trucks when the option was first offered) told us in a training class that the drain plug was eliminated to help assure that mechanics (or owners) would actually be required to "drop the pan" to change the ATF and therefore change the filter as well. I don't know if Borg was the first to delete the auto trans drain plug but it was only a few years till there were no auto trans drain plugs (so far as I know). They may have deleted it just so they could save a buck or 2 on the expense of producing the pan. Even back then there were a lot of ways to "spin" reasons for corporate decisions.

i changed the oil in my K46 last year after 300 hours of HARD work. it was black as could be, but not sludge. the hydro's only symptom was it seemed to slow down after about 4 hours of cutting, hey i have a big yard. the slow down was not drastic, but noticable though it took me a while to figure it out. i timed myself making a pass when i first started cutting, then 4 hours later drove the exact same pass WOT foot to the floor and it took almost 1/2 minute longer for the 418ft run! like i said,, not a drastic slwo down, but enough that it was taking as long to cut the final acre as it did to cut the first couple.

after i changed the oil, i get consistent speeds from start to finish and i finish close to 1 hour sooner.

Very good posts (a lot better than trying to get a job (ready to mow) as a John Deere salesman or telling how a dad had to trade cars frequently because of poor maintenance). I had time to do a little research today and I'm impressed at how correct you both were. From what I read, the common link in all modes of oil degradation is heat. Be it from compression heating of entrained air/moisture or heating from coming into contact with hot surfaces. And as you might expect, the degradation is exponentially linked to temperature and will result in particulate and acidic byproducts in the oil. Because of this, I think one of the most overlooked maitenance procedures is keeping the transmission housing clean. On my previous murray (I don't know the tranmission type), after many years it began to get "weak". I looked at the transmission for signs of problems and much to my surprise, the entire trans was coverd in a combination of fine dust (very thick in places), fine grass and what I would describe as caked on gunk. I washed the trans with a garden hose and got a few more years of service with no problems (I finally replaced the murray (after they went under) because of cummulative problems with the mower that were taking too much time to fix). Needless to say, I now blow off the trans of my Broadmoor pretty frequently.

Not to change the direction of this thread, but...
Do you think part of JD's reasoning for having a "non-serviceable transmission" could be marketing as well. The car manufacturers are always talking about not having to change their new "antifreeze" for 100,000 miles or having computers that extend the oil change interval, or lifetime brakes, mufflers, etc. Some big box buyers (probably none on this forum) might look at it as one less thing to have to check/maintain.

Volvo's approach with transmission fluid is to say that it is lifetime, and never needs to be changed (except in the fine print where they say change at 52k if tow a trailer). They do provide a drain plug, which seems to contradict their claim, but everyone sort of acknowledges that it is pure marketing, and most tech's view regular changes as good maintenance.

Hello,
Can anyone tell me what type of engine oil/viscosity to use in my Kawasaki 18HP V Twin Motor, would you advise Fully Synthetic?

I would also like to know what type of oil/viscosity to use in the K46 Hydro transmission (I think thats whats in my mower) and is anyone knowledgeable enough to point by point explain how to do a complete transmission oil change or does anyone have a .PDF on the tranny? I'm thinking definately sythetic oil in there as well?

I also need to kow oil capacities for both and a reassurance that the whinning noise or "growling" as some say is normal for this tranny?

Thankyou very much in advance, it seems there isn't much you guys don't know.

Okay, I just may owe you guys $600 for a new tranny in my L130. My L130 starts losing power after about 20 minutes of use until it just won't go anymore. Reverse is quite a bit quicker to go. I'm gonna go with a oil flush and change and see if this does the trick. It sure would be nice if my friendly JD Service rep would have suggested this first instead of quoting me a new one.
Really, thanks a bunch!
Bob

Friend of mine just bought a sleeve hitch for his K46 powered Craftsman "yard" tractor. That should put it to the test. Kind of odd that Sears sells a tractor which isn't designed for a sleeve hitch, yet still has the holes pre-drilled for it.

Not all Tuff Torq Trannys are bad (and it is debatable, as you can see from above posts, if the K46 is good/bad and what they are good/bad for). Tuff Torq's higher end trannies are actually very reliable.

My K71 pulls like a mule. I'm sure there's nothing wrong with the K46. Tuff Torq doesn't market it as a ground-engaging transmission.

However, my Dad's JD 265 is moved around by a Sauer-Sundstrand hydro, known for skid-steer transmissions. And the transaxle has a spin-on oil filter. Seems like a bit more rugged than the transmissions they all use now.

My '96 Cub 2185 46" and '98 1646 Deere Sabre are each running strongly and quietly on their 2nd HST filters. Factory originals changed on schedule but tranny dipstick looks so good in each that service has been postponed until "next season" for 10 years now. 600hrs on the Cub, 700hrs on the Sabre. Same for engine filters but top off with SAE30 as needed.

I have a JD 1646 Hydro lawn tractor, my service guy tells me
it is junk. I bought this at an auction and was assured by the owner's family that it was serviced often and taken very good care of by a local shop. Well, that being said I don't know who to believe I just dropped $100 just to have a guy "look at it" He took the tranny out and said that it was bone dry and was burnt up. The tranny number is a Tuff Torq 00752, I cannot afford a new tranny and will have to buy a used one. Any help with information or where to buy a used one would be great.

the tuff torq can use regular or synthetic oil, standard 10w30 auto engine oil is what is included. this is right off their web page.

i know an expert mechanic who keeps his cars and he gave me the simple advise to use all synthetic fluids if possible. they cost more but if you plan to keep your vehicle (or tractor) they are worth the extra money - don't break down as quickly, more resistant to high temperature, key in a tractor transmission.

the other thing to consider is the oil change pumps with the skinny tube which goes down the dipstick hole - you start the flow by hand and then the oil is siphoned out into the pump tank. simple as pie and this would work for something like a transmission with a top fill plug only.

so does anyone have a 2346xls yet and have you blown a ton of snow or towed something heavy? what i really want is a GT with locking diff. dont want 4wd. the only one i have found with locking diff is 2346xls husky or the simplicity conquest which is pricey 5-6K.

My K71 pulls like a mule. I'm sure there's nothing wrong with the K46. Tuff Torq doesn't market it as a ground-engaging transmission.

I wonder why all the sears tractors rated for "ground-engaging" use that same Tuff Torq K46.
I wet through today and looked at them all and the part books showed the same part number for the trans-axle.

MY LX-76 I believe had a TUFF-TORQ tranny seviced it every 5 years light service, synthetic 10w-30 oil sold it an it runs great . My X534 has a k-72 in it, I believe and it is a bear. If you service it regularly it will treat you well ,,, unfortunately nothing is perfect.

My '06 Craftsman YS4500 with the K46 tranny really started to get loud and I noticed it was beginning to slow down. I have some hilly areas and I think that pulling my loaded yard cart, weighted aerator, etc... on my 1.5 acre property began to take its toll. I believe this was beyond the engineered limits of this machine and would have eventually led to a premature death in the form of a tranny failure.

I'm not slamming any particular product here and am just reporting what I experienced. The tractor was a great lawn cutter and would have probably worked well for a long time on a flat property. I actually sold it for about $ 300.00 less than what I paid for it new, although I did add a few bells & whistles - wheel weights, steering wheel spinner, front bumper and a mulch kit w/gator blades.

I sold it after purchasing a used 2002 Toro Wheel Horse 522xi garden tractor. This is the right tractor for me and my property needs and should hopefully last for many years to come.

Ugh! I too have the k46 tranny in my l120 JD and am having all kinds of problems. After an hour going up a hill is nearly impossible. Don't have the cash for a new mower so I'm going to try replacing the tranny fluid. I assume since it's not serviceable you have to take off the pan/box. How do you fill it back up and what kind of tranny fluid do you use?

This has nothing to do with Hydrogear vs Tuff Torque. These are entry level transmissions on entry level lawn tractors. Similar to what comes in the CC 1000 series. In terms of reliability, the Tuff Torque K61, K66 and K72 are unmatched.

When changing the oil in the K46 they recomend 5W50 synthetic oil now. If you can't find it in a store nearby you can order it from the Tuff Torq corporation site.
Go to the Tuff Torq corporation site.

I was having a lot of trouble with my lawn tractor losing power. I decided to find out why. After doing a little searching on the internet I found that I needed to change the oil in it. When I pulled out the sealer cap and the removed the magnet I found gritty sludge stuck to the magnet. I decided to take my transmission apart and clean it out real good. Everything went well untill I started to put it back together. The hydraulic pumps inside are a devil to reasemble. Especialy the one driven by the pully shaft on top of the tranny.
I found out also that it has TWO magnets and a small filter inside. The filter was really dirty.
There are two small steel balls inside that are really easy to lose. If anyone takes they'rs apart like I did be very carefull not to lose them.
I got my tranny all put back together now and am waiting for a new sealer cap and vent. I had to order those.
I am writing this to let folks know that sometimes just changine the oil may not be enough. You might have to do what I did and give it a good cleaning out. Especialy that fiber filter. It gets full of grit and sludge. I don't recomend disasembling the pump housing at all. I lost one of the tiny steel balls. Lucky for me I had another one.
The upper rotary pump (the one driven by the pully shaft ) is very hard to reasemble. I went to the Tuff Torq site and they recomend 5W50 synthetic oil in place of the 10W30 now. I had to order that too.
Best of luck with all your endeavers.

Is it possible, or should I say practical, to drill the bottom of a K46 and install a drain plug? I assume the case would have to be disassembled to remove any metal shavings from drilling. It seems I read somewhere that on many mowers you have to remove the tranny to get to the fill cap. If that's true there probably isn't much point in a drain plug.

Hello, I am new to the forum, so please bear with me. This January I bought a John Deere X300 with all of the toys - 44" snowblower, weights, chains, mulching kit, full winter cab and bra. It's a great tractor, but I was possibly misled as to its ability to do yard work, as it has (according to the JD specs) a k46 transmission. Having said that, I went to the Tuff Torq site and looked at the specs for the k46. According to Tuff Torq, the axles on the k46 are 3/4" diameter. When I measured the axles on my X300 using a micrometer, they are exactly 1" diameter. When I then checked the Tuff Torq site again, the first transmission that they list as having 1" axles is the k58. Even the k57 has 3/4" axles. I sent am email to the Tuff Torq people to see if they can advise, but if anyone here knows, feel free to jump in. I want to be able to use a Brinly 10" moldboard plow and possibly a disk-harrow. If it has a k58, then it might be OK, but if not? If all this tractor is good for is cutting grass and blowing snow, I could have bought the L-100 series and saved about $2K. Thanks for any input you may have - Ken.

mamod, sounds like you needed a Garden Tractor and bought a Lawn Tractor. Did you tell the dealer you wanted to use ground engaging equipment when you bought it? I can't believe they would have recommended the X300 if they knew that.

Hi metal - seems that I may not have made myself completely clear to the dealer. That being said, I can't understand JD making a tractor (let's say the LA-135SE) for $2000, then making the X300 for another $1000 more, when it has the same transmission in it? Heavier frame and steering components, etc., but still just a lawn mower that does exactly what an LA-135 does - makes no sense. Then, as I had said in my post, the axles are 1" and the k46 according to Tuff Torq are only 3/4". This leads me to believe that the X300 may have a more robust transmission, which might work out if that's the case. I am losing my faith in John Deere. The more I read about them, the more I wish I hadn't bought one. Too many models, too many variables and in the end, a ton of money for something to cut grass and not a whole lot more. I was also considering putting an additional electric cooling fan (12 volt unit) on the transmission to make sure that it gets a lot of air while in use. This can be disabled in winter when it's not needed. Ken.

If you change the fluid in a non-servicable tranny like the K46 or K58 your warranty is gone as in bye bye. The techs can test to see if there is a different fluid type than it came with or they can tell if the amount of fluid has changed. I would feel better changing my fluid too but I would wait until the machine in question is out of warranty to do so or have the dealership do it.

i use my 16 hp regent w/ a k46 tranny to blow snow in the winter also and just a week ago i got stock spun the wheeles a lot then we got it out but later that morning it started to go slower called simplicity and they said to replace the drive belt no change it would run for about an hour then loose almost all power to move. any answers?

Cramer -
prolly best to start a new thread - this one is old and long. Yer apt to get more/better replies that way.
M/W, chk your tranny fluid level per yer manual - also "smell" it for signs of overheated oil. Change oil/filter per manual if so.

More likely than not you burned the oil in the transaxle and the only thing you can do is R&R the transaxle, replace the oil, and hope that solves the problem. If not, then a new transaxle is in your future.

The X300 has a 3/4 inch axle, my 2010 model. Yes measuring the axle between the trans and wheel measures 1 inch, but that is a sleeve over the axle. Remove the plastic cap on the outside of the wheel- there it measures 3/4 inch.

I have a JD L-118 that has the loss of power when hot problem. A previous mower (Murray) had a Dana-Spicer transaxle with the hydro unit attached to it by a couple of bolts and driven by socket drive. The hydro unit could be removed and replaced without completely disassembling the transaxle. A much better idea. I used that mower for many years with no problems from the hydro unit. Other problems with the mower, but not the hydro drive.

I have a Husqvarna YTH2042 with a K-46 tranny. After 200hrs over 4 yrs and a lot of research I decided to change the transaxle oil. Contacted Tuff Torq engineering and they told me the USA and Canada are probably the only countries that don't order the option of two drain plugs in the bottom case. They e-mailed a detailed drawing indicating the two bosses where the drain plug holes are located. I pulled the tranny, drilled the holes,flushed the tranny a coup[le of times with cheap oil and filled it with 5W-50 synthetic oil and installed the two drain bolts supplied by Tuff Torq. Did this last summer and it's still working great. BTW- The engineer said this was about a 50 cent option.

justalurker...You are probably right on the reasons for omitting the drain plugs. I would think Tuff Torq would not option these items and put them on all trannys. They are taking a hit on their quality reputation. Seems it would be better to put them in and if the tractor manufacturer wanted to claim them as unserviceable the liability would be on their heads. Are you listening Tuff Torq???

Having been involved in decisions of this type and at that level I can tell you that marketing and product liability people have more weight in this kind of discussion than engineering people and the component manufacturer has no vote at all. TT listens to the OEM and reads the contract put in front of them.

The end user needs to punish the manufacturer for not listening not blame or criticize the component manufacturer who will happily provide whatever the OEM desires. Want drain plugs? Then vote with your wallet... simple as that.

I blew a rear axle shaft seal on my Ariens Riding Mower. Needles to say it made a mess. I did replace the seal and filled the engine with W10-30 oil. The dipstick shows OK, but how do I fill the Trans Axle? It makes some noise. I think it is empty.
Thanks, Hans G Brehm

I have a tuff torque K46 in my John Deere L118.
As described, my transmission was slipping big time and could not even make it up the slightest grade. I dropped the transmission out and open the vent cap and drained out all the oil. I then replaced it with two quarts of moble full synthetic 10w-30 . The transmission now works better than when it was new and will climb any hill with ease, with no slipping or that loud whinning noise. This web site just save me thousands....between replacing the transmission, $1000, or a new tractor, $3500!!!!!!

The life of a hydrostatic transmission will be determined by heat,fluid level and the life of seals and gaskets. There is very little wear on the internal parts of the transmission (less the rear end)Breakdown of the oil from heat and low level of oil will kill the transmission. Once their is slipping when it get hot, the damage is done and will just get worse. If you cannot hold your hand on the transmission when it is hot, its too hot.

A Sundstrand/Hydrogear and Tuff Torq can be repaired, but dealers only replace the units. Have a hydraulic shop lap the cylinder blocks/thrust plates and valve block and its good as new. They only take about a few thousands of an inch off the surfaces and make they smooth again without any grooves in them. These parts can be lapped by owner using a smooth flat glass or flat granite plate, 320 to 600 grit wet/dry sandpaper and mineral spirits. Rotate the parts on the paper in a figure 8, while holding them down and flat. You should be able to get the grooves and scuff marks off. Wash these parts and make sure they are very clean and reinstall with oil on all the critical surfaces. Keep everything clean, it is everything.

I pulled the K46 from my X300 a couple years ago at 50 hours and drained and replaced the oil with 5W-50 synthetic. Took a total of about 1 hour. Got rid of the cheap factory oil JD asks for. It's been running fine, now at 175 hours. Keep it clean and cool. For FULL information on servicing the K46 search for "TuffTorq K46 Repair Guide with Pictures" on the internet.

Thanks to everyone for the information above, it helped me to breathe some life back into my 19 year old JD Sabre 1646. It wouldn't hardly move in reverse when hot (I changed the fluid last season 10w30 conventional per manual for the same reason). I was lucky enough to have drain plugs, so I thought that I might as well experiment a little. After draining the tranny overnight, I refilled it with Mobile 1 15w50 synthetic. The hydro behaves like new (better?), with no fading even after 65 minutes of mowing. I don't use it at all when cold out so l thought the 15 base weight was worth a shot.

My 7 year old Craftsman YS4500 slowed to a crawl, especially in turns.
Found this forum and received some good info, particularity from "Mowie".

Pulled the K46, drained the fluid. It was darkish gray in color. Replaced with two quarts SAE Non detergent 30w that I bought from Autozone. Cleaned it good and re-installed. It works better than ever.

A couple of hours on the garage floor, $8.00 worth of oil and replacing my wife's glass measuring bowl -vs- several hundreds of dollars to repart/repair/replace!!!

I hope everyone finds this forum as useful as I have.
Happy Mowing & Stillhere.

Note to those of you commenting on these posts about putting a drain plug in the transaxle and also those describing draining the transmission by siphoning the oil out of the fill plug.

This transaxle has 2 completely separate chambers in it that both contain oil. One side has the drive gears (the side with the big "bump" out on the bottom pan) and the other side has the hydro pump and motor. The two side are only connected by the fill port area where the magnet sets into.

If you do wish to install a drain plug in the bottom pan you will need to put one in each side to drain both chambers.

In a similar fashion, if you are going to siphon out oil to change it you will have to get your siphon tube inserted into both the fill openings under the fill cap.

Just pull the transaxle and invert it to drain. DO NOT try to pull out the vent, you will break it. Fill cap is under the fan/pulley which has to be removed to access the cap and drain.

While the transaxle is out it is a good time to clean it up and inspect it.